The league banned Blackmon on Tuesday for the first four games of the 2013 season for his second violation in less than a year.
Bradley followed a similar path of general manager Dave Caldwell, offering support to Blackmon, who led the team in catches as a rookie last season.
"I told Justin I do trust him," Bradley told the Florida Times-Union on Thursday. "We both have to earn each other's trust, and I don't want trust to be mistaken for being naive."
Bradley also told the newspaper he has had "six or seven" conversations with Blackmon since the league alerted the team and player of the ban.
"He understands we're disappointed in what took place," Bradley said. "I really try to maintain my focus on making sure he has a clear vision of what we expect from him. We've had great conversations since this came out."
Blackmon, who apologized in a statement after his suspension was handed down, caught 64 passes for 865 yards and five touchdowns as a rookie after being selected fifth overall out of Oklahoma State.